Reducing corrosivity of solvent casting compositions

ABSTRACT

This invention provides a non-corrosive solvent casting composition comprising at least one anti-corrosive selected from the group consisting of (a) non-volatile epoxides; (b) oxides of compounds from the group consisting of styrene, higher homologs of styrene, and simple nuclear substitution products of styrene; (c) 2,2-dimethoxy propane; and (d) 1,4-dioxane.

United States Patent [191 Waring 51 Feb. 20, 1973 [54] REDUCING CORROSIVITY OF SOLVENT CASTING COMPOSITIONS [75] Inventor: James R. Waring, Binghamton,

abandoned.

[52] US. Cl. ..106/l4, 106/181, 106/189, 117/6, 252/387, 252/396, 260/45.7, 260/47 [51] Int. Cl. ..C09d 5/08 [58] Field of Search ..106/l4, 181, 189; 260/45.7, 260/47; 117/6; 252/388, 387, 396

[56] References Cited UNITED STATES PATENTS 2,927,036 3/1960 Seavcr ..106/I8l X 2,999,837 9/1961 Franzus ..260/45.7 3,399,172 8/1968 3,428,468 2/1969 3,582,368 6/1971 3,411,923 11/1968 2,930,708 3/1960 Chatfield ..106/14 Primary ExaminerDonald J. Arnold Assistant Examiner-David A. Jackson Attorney-George L. Tone, W. C. Kehm and S. B. Leavitt [5 7 ABSTRACT This invention provides a non-corrosive solvent casting composition comprising at least one anti-corrosive selected from the group consisting of (a) non-volatile epoxides; (b) oxides of compounds from the group consisting of styrene, higher homologs of styrene, and simple nuclear substitution products of styrene; (c) 2,2-dimethoxy propane; and (d) 1,4-dioxane.

16 Claims, No Drawings REDUCING CORROSIVITY F SOLVENT CASTING COMPOSITIONS This application is a continuation of my application Ser. No. 790,431, filed Jan. 10, 1969, and now abandoned.

This invention relates to solvent casting compositions, and, more particularly, to solvent casting compositions comprising at least one anti-corrosive material.

The formation of products such as film by solvent casting compositions such as polycarbonate and cellulose derivative-containing dopes on continuous metal bands, particularly stainless steel bands is a process of considerable economic importance. However, continuous casting on metallic bands has led to corrosion thereof as evidenced by fine pits over the polished surfaces of the band. As a result, film or other articles cast thereon has an unsatisfactory finish. Accordingly, much research has been devoted to finding substances which would prevent corrosion of the metallic bands upon which solvent casting is done without interfering with the speed of the process, the quality of the products, and the costs of the operation.

It is an object of this invention to provide anticorrosive materials for use in solvent casting compositions, particularly those cast upon metallic bands, which are effective at low levels of concentration.

It is also an object of the invention to provide anticorrosive materials use in solvent casting compositions which do not adversely affect the product made from the solvent casting process. Another object of the invention is to provide anticorrosive substances for use in solvent casting compositions which are readily available, readily soluble or dispersible in solvent casting compositions, and relatively non-volatile at the reaction conditions of solvent casting in general.

Accordingly, the invention provides solvent casting compositions comprising at least one anti-corrosive selected from the group consisting of: (a) non-volatile epoxides; (b) oxides of compounds selected from the group consisting of styrene, the higher homologs of styrene, and simple nuclear substitution products of styrene; (c) 2,2-dimethoxy propane; and (d) 1,4-dioxane.

The anti-corrosives of this invention are particularly suitable for use in solvent casting compositions from which film is made and especially those containing polycarbonates, e.g. those obtained by reacting bisphenol A and phosgene, or those containing cellulose derivatives such as cellulose triacetate, cellulose acetate butyrate, and the like. Such compositions commonly contain, besides the cellulose derivative, one or more solvents such as cyclohexane, methanol and methylene chloride, and one or more plasticizers such as triphenyl phosphate and dimethyl phthalate.

Such compositions can be cast in a continuous process upon stainless steel bands, and other metallic as well as metal-coated bands subject to corrosion by the ingredients of the casting composition.

As used herein, the term non-volatile means nonvolatile at the conditions of temperature and pressure prevailing during the solvent casting processes in which the solvent casting compositions of the invention are employed.

The anti-corrosive, non-volatile epoxides of the invention include esters of saturated and unsaturated higher fatty acids and of saturated and unsaturated cycloaliphatic carboxy acids, particularly those containing from about 8 to 20 carbon atoms, epoxides of aryl and alkyl esters of unsaturated alcohols, particularly those containing at least 5 carbon atoms, and low molecular weight cyclic-aliphatic epoxides containing two epoxide groups per molecule in the cyclic or aliphatic portion of the compound, or in both. The epoxides of the invention can be monoor poly-epoxides containing from 1 to 25 epoxide groups per molecule or from 1-25 percent oxirane oxygen, depending upon the nature of the epoxide or epoxides used, the amounts employed, and the nature and amounts of ingredients in the casting composition itself.

Examples of epoxides useful in the composition of the invention include the poly-epoxide made from epoxidized soybean oil, and marketed under the tradename EPOXOL 7-4 by Swift and Company, and containing on the average 4 reactive epoxide groups per molecule or about 7 percent oxirane oxygen; the poly-epoxide bearing the tradename EPOXOL 9-5 from Swift and Company, containing over 9 percent oxirane oxygen or an average of five and one-half epoxide groups per molecule; and epoxidized soybean oil from Union Carbide Company, marketed under the trademark FLEXOL EPO and containing 7 percent oxirane oxygen; 2-ethylhexyl-9,IO-epoxyphthalate, an example of which is a product marketed under the tradename FLEXOL EP-8 by Union Carbide Company, and containing 5 percent oxirane oxygen; an epoxy ester marketed'under the name FLEXOL GPE from Union Carbide Company; and epoxides such as di-(isodecyl)-4,5-epoxy tetrahydrophthalate, an exam ple of which is the product marketed under the tradename FLEXOL PEP.

Examples of the epoxides of aryl, aralkyl and alkyl esters of unsaturated alcohols, particularly those containing at least five carbon atoms are the glycidyl ethers, such as phenyl and alkyl glycidyl ethers.

Low molecular weight cyclic-aliphatic epoxides containing two epoxide groups per molecule in the cyclic or aliphatic portion of the molecule, or in both, include l-epoxyethyl-3 ,4-epoxycyclohexane, 3 ,4-epoxycyclohexylmethyl-3,4 epoxycyclohexanecarboxylate, and bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate. Typically, amounts of these epoxides ranging from less than 0.1 to about 2.0 percent based on the I overall solvent casting composition are used, but preferred amounts will vary, even outside this range, depending upon the epoxide and film-forming substances used.

Although the amounts of the nonvolatile epoxides used in the solvent casting compositions of the invention vary widely depending upon the metallic band upon which the casting solution is cast, the nature and amounts of the ingredients in the casting composition itself, and the nature of the epoxide or epoxides used, the following ranges are suitable for use with cellulose derivative-containing solvent casting compositions cast 100 grams of cellulose derivative solution or dope; for the epoxides of aryl and alkyl ester of unsaturated alcohols, particularly glycidyl ethers such as phenyl and alkyl glycidyl ethers, from 0.8 to 6.5 grams per 100 grams of cellulose derivative solution or dope.

Similar considerations effect the choice of amounts of anti-corrosive employed when styrene oxide, higher homologs thereof, and simple nuclear substitution products thereof are used; however, when these materials are used with cellulose derivative-containing solvent casting compositions, a generally useful range of amounts is from 0.2 to about 5 grams of anti-corrosive per 100 grams of cellulose derivative solution. For 2,2- dimethyoxypropane, when used with cellulose derivative-containing solvent casting compositions, a generally useful range is from 0.25 to 2.0 grams of the anti-corrosive per 100 grams of cellulose derivative solution. 1,4-Dioxane proves an effective anti-corrosive in the cellulose derivative-containing solvent casting compositions in amounts up to about 4 grams of anti-corrosive per 100 grams of cellulose derivative dope.

The following examples clearly illustrate that the anti-corrosive solvent casting compositions of the invention reduce significantly the corrosivity of cellulose derivative-containing solvent casting compositions. However, the examples are not furnished to limit the scope of the invention, but only to illustrate the effectiveness with the classes of solvent casting composition shown. The scope of the invention is limited only as defined in the appended claims.

EXAMPLE I Cellulose triaeetate ester, g Recovered filmbase, g

Triphenyl phosphate, g Dimethyl phthalate, g. Flexol EPO I Cyclohexane, g Time to corrode steel bars, hours EPO 30 2/ Epoxol The amounts of cellulose derivative and anti-corrosive were sufficient to yield a viscosity on the order of about 80-100 ASTM seconds. The corrosion of the solvent casting compositions modified with epoxide anti- 5 corrosive was compared to control compositions containing exclusively recovered cellulose derivative or cellulose derivative in combination with triphenyl phosphate and dimethyl phthalate in a 3:1 ratio. The effectiveness of the anti-corrosives was measured by means of a steel bar partially immersed in the composi- TABLE I Cellulose Triacetate Ester 10.65g l0.65 10.65 10.65 10.65 10.65 Recovered Filmbase 5.353 5.35 5.35 5.35 5.35 5.35

Triphenyl Phosphate 120g L 1.20 1.20 1.20 1.20 Dimethyl Phthalate 0.403

1} Flexol 0.40 3/ Epoxol 9-5 0.40 4/ Flexol GPE 0.40 5/ Flexol Methylene Chloride 73.75g 73.75 73.75 73.75 73.75 73.75 Methanol 7.833 7.83 7.83 7.83 7.83 7.83 Cyclohexane 0.823 0.82 0.82 0.82 0.82 0.82

asHCl ll 6 6 6 5 6 4O acidity as 11 See footnotes, Table III.

Recovered cellulose triacetate iilmbase, g Flexol EPO l Flexol GPE 4 Flexol EP-8 5 Epoxol 7-4 2 Methylene chloride, g

Methanol, g Cyclohexane, g Time to corrode steel bars, hours 1 Flexol EPO is an epoxidized soybean oil from Union 2 Epoxol T-14 is a polyepoxide (epoxidized soybean oil) groups per molecule or 7% oxirane oxygen.

Carbide Company containing 7% oxirane oxygen. from Swift and Company containing on the average four reactive epoxide 3 Epoxol 9-5 is a polyepoxide from Swift and Company containing over 9% oxirane oxygen or an average 01' 5,; epoxidc groups per molecule.

4 Flexol GPE is an epoxy ester from Union Carbide Company. 5 Flexol EP-S is 2-ethyl, hexyl-9,10-epoxytallate from Union Carbide Company containing 5% oxirane oxygen.

5 P.p.m. is an abbreviation for parts per million.

EXAMPLE n A cellulose acetate butyrate solvent casting composition was prepared as follows: To a solvent system of methylene chloride, sec-butanol and cyclohexane was added either virgin cellulose-derivative, recovered cellulose-derivative, or a combination thereof. Anti-corrosive was added in the amount of about 2 percent to percent by weight of the cellulose derivative. The amounts of cellulose-derivative and anti-corrosive were sufficient to yield a viscosity on the order of about 80-100ASTM seconds. The corrosion of the compositions modified with the anti-corrosives shown was compared to control compositions containing exclusively recovered cellulose-derivative or cellulose-derivative plasticized with triphenyl phosphate trioctyl phosphate in a 3:1 ratio. Measurement of the results was by means of a steel bar partially immersed in the compositions within a sealed pint bottle at ambient conditions. Table IV shows the results.

iliubasc, g 'lriphcnyl phosphate. Trioctyl phosphate Sec-butanol, g (Jyclohexane, g Time to corrode steel bars, hours See footnote, Table III.

7 Flexol PEP is an cpoxidc from Union (jarbon Carbide Company containing 3'7}, oxygen culled di (isodm-yl) 4,5-vpoxy tutrahydrophthalatc.

EXAMPLE III A cellulose triacetate solvent casting composition y y} the containing from 60.4 to 61.2 percent combined acetic acid was prepared as follows: To a solvent system of methylene chloride and methanol was added sufficient epoxide-anti-corrosives to effect the reduction in corrosion. To this mixture was added 100 parts of virgin cellulose derivative, 15 parts of a plasticizer combination of triphenyl phosphate and dimethyl phthalate in a ratio of 3:1 and variable amounts of recovered cellulose-derivative to yield a composition with a viscosity on the order from about 80 100 ASTM seconds. The

corrosion was compared to a control composition containing no corrosion inhibitor by partially immersing a steel bar in the composition within a sealed pint bottle at ambient conditions, or alternately, by analytically determining the key corrosion parameter of chloride, and the secondary parameters of acidity and water content. The results are shown in Tables V and VI.

as HC] 8 1 1 7 a kacidity asacetic acid 0.0045 0.0053 0.004%.0043 0.0090 0.0060 %water 0.12 0.08

"Too smalltobedetected TABLE VI Cellulose Triacetate Ester 9.713 9.71 9.71 9.71 9.71 9.71 Recovered Filmbase 7.53; 7.53 7.53 7.53 7.53 7.53 Triphenyl Phosphate 1.09; 1.09 1.09 1.09 1.09 1.09 Dimethyl Phthalate 0.36; 0.36 0.36 0.36 0.36 0.36 Methylene Chloride 711.58g 71.96 735872.77 72.77 67.10 Methanol 7.733 7.73 7.73 7.73 7.73 7.73 Alkyl 1 n h a '1 in I 4.0 I I i i is 338 33 538 Glycidyl Ether 1.62 0.81 Phenyl 0.81 6.48 Pp asHCl 8 1 9 3 5 1 EXAMPLE IV A cellulose acetate butyrate composition was prepared as follows: To a solvent system of methylene chloride, sec-butanol and cyclohexane was added sufficient 1,4-dioxane to effect a reduction in corrosion. To this composition was added 100 parts of virgin cellulose-derivative, two parts of the plasticizer combination triphenyl phosphate and trioctyl phosphate in a ratio of 3:1 and variable amounts of recovered cellulose drivative, or alternately, of formula containing recovered cellulose-derivative exclusively. With either formulation, the viscosity should be on the order of about ASTM seconds. The corrosion was compared tov a control composition containing no corrosion inhibitor by partially immersing a steel bar in the composition EXAMPLE V A cellulose triacetate composition containing from 60.4 to 61.2 percent combined acetic acid was prepared as follows: To a solvent system of methylene variable amounts of recovered filmbase to yield a dope having a viscosity on the order of 80100 ASTM seconds. The corrosion was measured by the analytical determination of the corrosion parameter of chloride.

chloride, methanol and cyclohexane was added suffi- 5 low chlon'de content indicating low corrosivity.

TABLE I);

i 1 a i s u 7 s .1 10 11 12 Cellulose triacetate ester, 5: El. 71 J. 71 .71 9. 71 .1. 71 11.71 71 u, 71 9, 71 9, 71 g, 71 9 71 Recovered fi1 ba e g 1.53 7.53 1.53 7.53 7.53 7.53 7.53 7.53 7.53 7.53 7.53 7.53 .mphenymhmphate, g H r09 1.0!) 1.00 1.011 1.09 1.00 1.09 1.00 1.09 .09 1.00 1.09 Dimeili l phthalate, g... .3 0. .3 0. 30 0.36 0.36 0.36 0. 36 0. 36 e36 (13 Methylene chloride, g. 73.58 73. 48 3.38 73.18 72.78 73.48 73.38 73.18 72.78 73,53 73 33 7 t a g 7 73 7.73 7.73 7.73 7.73 7.73 7.7 7,73 Unox Epoxide:

ggg g P l 4 4 A .i 0.2 0.4 0.8 s o 2 1 U 0.1 0 .2 g i I 0. 2 1. 0 I.p.m. Cl as HCl.

(3) r, 1 i l 2 1 4 1 T00 small to be detected. l'POXldC). Replicate tests for Unox Epoxidc .206 and 221 at 6 and 5 p. ).m. Unox Epoxide .221, which is 3,4-cpoxye l h chloride on control rlopc. i-yclohexiinecarhoxylzitc, is :1 (liepoxidc made by the Union Carbide 8 Unox Epoxide 206, which is l-epoxyethyl-3,4-cl oxycyclohexanc, is a Corporation having 11.4% by weight of oxirane oxygen. diepoxide made by the Union Carbide Corporation having an epoxide w Unox Epoxidv 28), which is his (3,4-ep0xy-6miethylcyclohcxylequivalent of 74-78 (grams of resin containing one gram equivalent of methyl) adipute, is a diepoxide from Union Carbide Corporation.

cient dimethoxypropane to effect a reduction in corro- The above examples indicate that the amounts of sion. To this composition was added 100 parts of virgin corrosive materials such as chloride ion, acidic ions and cellulose-derivative, parts of a plasticizer combinawater are reduced substantially by incorporating in the tion of triphenyl phosphate and dimethyl phthalate in a casting compositions at least one anti-corrosive within ratio of 3:1 and variable amounts of recovered celluthe scope of this invention. The result produced by lose derivative. Alternatively, a composition containing reducing the amounts of these materials in the solvent recovered filmbase exclusively can be used. With either casting compositions is to prolong the time required to formulation, the viscosity should be on the order of corrode steel bars partially immersed in the solvent about 80-100 ASTM seconds. The corrosion occurring casting compositions of the invention. For example, was compared to that produced by a control composi- Table II shows, in runs 7,8 and 9, that omission of antition ontaining no orro ion inhibito b ti ll i corrosives within the scope of this invention resulted in mersing a steel bar in the om o ition ithi a l d corrosion time substantially lower than that obtained int bottle at ambient onditions, Th e lt are when at least one anticorrosive within the scope of this detailed in Table VIII. invention was included. Similarly, comparing results obtained in control run 1 of Table III with results ob- TABLE VIII tained in runs 2 through 9 in which at least one anti- 40 corrosive within the scope of the invention was inl 2 3 4 5 6 eluded indicates that the corrosion time was significantly increased by the presence of at least one anticeuulose corrosive. Similar results are indicated in all the experi- Triacetate merits tabulated in the above examples. Ester ed Though this invention has been described with Recover Filmbase 7.6g 76 709 709 709 709 reference to certain specific embodiments, it should be Triphenyl understood that the invention is not limited except as Phosphate L03 defined in the appended claims. Trioctyl Phosphate 0.34 0.34 0.34 0.34 i Methylene Chloride 733758 71.75 7375 7350 7325 7175 l. A casting composition consisting essentially of a Methanol 7.83g 7.73 7.73 7.73 7.73 7.73 solution in an organic solvent medium selected from g i g zzzx Q82 032 the group consisting of cyclohexane, methanol, ;,yprpane LOO O15 050 L00 methylene chloride, sec-butanol and mixtures thereof, Water 0.17 0.12 0.17 0.19 0.13 0.16 of a polycarbonate derived from Bisphenol A and steel Phosgene or cellulose derivative film-forming material bar, hours 24 48 163 240 240 240 selected from the group consisting of cellulose triacetate and celeulose acetate butyrate, said solution being per se corrosive to metal casting surfaces, and as EXAMPLE VI an anti-corrosive agent about 0.1 to 6.5 grams per 100 parts by weight of said casting composition of a F fif g triacetate (60A; llljercem combined member selected from the group consisting of epoxides acetic aci ope was prepare as o ows. To a solvent of esters of saturated and unsaturated CF20 y 'f of methylene chlol'lde and methanol was f f cycloaliphatic carboxy acids, epoxides of aryl and alkyl sufficlem p yp Solvent to effect a reductlon 65 esters of unsaturated alcohols of at least five carbon corrosion of the metal bands upon which the solution is cast. To this solution were added parts of virgin ester, 15 parts of plasticizer comprising triphenyl phosphate and dimethyl phthalate in a ratio of 3:1, and

atoms, low molecular weight cycloaliphatic epoxides containing two epoxide groups per molecule, styrene oxide, alkylglycidyl ether, phenyl glycidyl ether, 2,2- dimethoxy propane and 1,4-dioxane.

2. A casting composition as defined in claim 1 wherein said agent is 2-ethylhexyl-9,IO-epoxyphthalate.

3. A casting composition as defined in claim 1 wherein said agent is di-(isodecyl)-4,5-epox- 5 ytetrahydrophthalate.

4. A casting composition as defined in claim 1 wherein said agent is l-epoxyethyl-3,4-epoxycyclohexane.

5. A casting composition as defined in claim 1 wherein said agent is phenylglycidyl ether or alkylglycidyl ether.

6. A casting composition as defined in claim 1 wherein said agent is styrene oxide.

7. A casting composition as defined in claim 1 wherein said agent is 2,2-dimethoxy propane.

8. A casting composition as defined in claim 1 wherein said agent is 1,4-dioxane.

9. A self supporting film cast from a composition consisting essentially of a solution in an organic solvent medium selected from the group consisting of cyclohexane, methanol, methylene chloride, sec-butanol and mixtures thereof, of a polycarbonate derived from Bispheol A and Phosgene or cellulose derivative film-forming material selected from the group consisting of cellulose triacetate and celeulose acetate butyrate, said solution being per se corrosive to metal casting surfaces, and as an anti-corrosive agent, about 0.1 to 6.5 grams per parts by weight of said composition of a member selected from the group consisting of epoxides of esters of saturated and unsaturated C -ZO cycloaliphatic carboxy acids, epoxides of aryl and alkyl esters of unsaturated alcohols of at least five carbon atoms, low molecular weight cyclicaliphatic epoxides containing two epoxide groups per molecule, styrene oxide, alkyl glycidyl ether, phenyl glycidyl ether, 2,2-dimethoxy propane, and l,4-di 0xane.

10. A film as defined in claim 9 wherein said agent 18 16. A film as defined in claim 9 wherein said agent is 1,4-dioxane. 

1. A casting composition consisting essentially of a solution in an organic solvent medium selected from the group consisting of cyclohexane, methanol, methylene chloride, sec-butanol and mixtures thereof, of a polycarbonate derived from Bisphenol A and Phosgene or cellulose derivative film-forming material selected from the group consisting of cellulose triacetate and celeulose acetate butyrate, said solution being per se corrosive to metal casting surfaces, and as an anti-corrosive agent about 0.1 to 6.5 grams per 100 parts by weight of said casting composition of a member selected from the group consisting of epoxides of esters of saturated and unsaturated C8-20 cycloaliphatic carboxy acids, epoxides of aryl and alkyl esters of unsaturated alcohols of at least five carbon atoms, low molecular weight cycloaliphatic epoxides containing two epoxide groups per molecule, styrene oxide, alkylglycidyl ether, phenyl glycidyl ether, 2,2- dimethoxy propane and 1,4-dioxane.
 2. A casting composition as defined in claim 1 wherein said agent is 2-ethylhexyl-9,10-epoxyphthalate.
 3. A casting composition as defined in claim 1 wherein said agent is di-(isodecyl)-4,5-epoxytetrahydrophthalate.
 4. A casting composition as defined in claim 1 wherein said agent is 1-epoxyethyl-3,4-epoxycyclohexane.
 5. A casting composition as defined in claim 1 wherein said agent is phenylglycidyl ether or alkylglycidyl ether.
 6. A casting composition as defined in claim 1 wherein said agent is styrene oxide.
 7. A casting composition as defined in claim 1 wherein said agent is 2,2-dimethoxy propane.
 8. A casting composition as defined in claim 1 wherein said agent is 1,4-dioxane.
 9. A self supporting film cast from a composition consisting essentially of a solution in an organic solvent medium selected from the group consisting of cyclohexane, methanol, methylene chloride, sec-butanol and mixtures thereof, of a polycarbonate derived from Bispheol A and Phosgene or cellulose derivative film-forming material selected from the group consisting of cellulose triacetate and Celeulose acetate butyrate, said solution being per se corrosive to metal casting surfaces, and as an anti-corrosive agent, about 0.1 to 6.5 grams per 100 parts by weight of said composition of a member selected from the group consisting of epoxides of esters of saturated and unsaturated C8-20 cycloaliphatic carboxy acids, epoxides of aryl and alkyl esters of unsaturated alcohols of at least five carbon atoms, low molecular weight cyclicaliphatic epoxides containing two epoxide groups per molecule, styrene oxide, alkyl glycidyl ether, phenyl glycidyl ether, 2,2-dimethoxy propane, and 1,4-dioxane.
 11. A film as defined in claim 9 wherein said agent is di-(isodecyl)-4,5-epoxytetrahydrophthalate.
 12. A film as defined in claim 9 wherein said agent is 1-epoxyethyl-3,4-epoxycyclohexane.
 13. A film as defined in claim 9 wherein said agent is phenylglycidyl ether or alkylglycidyl ether.
 14. A film as defined in claim 9 wherein said agent is styrene oxide.
 15. A film as defined in claim 9 wherein said agent is 2,2-dimethoxy propane.
 16. A film as defined in claim 9 wherein said agent is 1,4-dioxane. 